tcpip client connection detecting server

Hi,

I have a MATLAB GUI which connectes as a client via TCP/IP from the instrument control toolbox to a server process, from which it gets asynchronous messages every so often.

 If the server process closes its side of the connection, nothing seems to happen on the MATLAB side; the BytesAvailalableFcn callback isn't invoked, nor is the ErrorFcn callback.

Is there any way of detecting when this happens?

Thanks in advance, Paul.